Abstract: A disintegrative member, such as a salt core, is provided with a vent opening extending through its thickness from an outer surface to an inner surface in order to allow gases to pass radially inwardly through the body of the salt core and away from a region proximate the salt core's outer surface. The escape of these gases through the vent opening decreases the likelihood that porosity will be formed as a result of those gases being trapped in a region proximate the outer surface of the salt core because the molten metal solidifies more slowly in this area because of the thermal insulative qualities of the disintegrative member.

Abstract: A composite core structure is used for metal casting in order to form cavities of preselected sizes and shapes within the casting. The composite core has an insoluble support member that can be metallic and a soluble portion disposed around at least a part of the support member. When the composite core is used in a casting process, such as a die casting process, the soluble portion is dissolved after the casting process is complete, and the insoluble portion is then removed from the cavity that was formed through the use of the composite core.